The present invention relates generally to optical communications, and more particularly to fiber optic communication systems.
Optical communication technologies are employed in a wide variety of communication environments. Examples of such communication environments include, but are not limited to, telecommunications, networking, data communications, industrial communication links, medical communications links, etc. In networking environments, fiber optics have traditionally been employed in the network core as long-haul backbones. More recently, fiber optic technologies have been implemented at the network edge, e.g., m metropolitan area network (xe2x80x9cMANxe2x80x9d) and local area network (xe2x80x9cLANxe2x80x9d) environments. Examples of other environments in which optical communication technologies are being deployed include network operation centers, corporate network backbone, central offices, and edge/core aggregation points.
As optical communications have been implemented in edge environments, an increased need has developed for optical interconnect equipment that is capable of alleviating bandwidth bottlenecks by using increased port densities to provide more links at higher speeds within a constrained physical infrastucture. At the same time that service providers are attempting to deploy such higher bandwidth solutions, they face market constraints that increasingly make such solutions more difficult to implement, e.g., reduced capital budgets, physical space limitations, HVAC (heating, ventilation, and air conditioning) limitations, increasing power costs due to limited power grid capacity, etc.
Modem conventional optical communication infrastructures commonly employ 1310 nm-based optical transmission technology for short, immediate, and some long-range links, while more expensive 1550 nm-based technologies are generally reserved to implement longer-haul requirements, often using dense wavelength division multiplexing (xe2x80x9cDWDMxe2x80x9d). Single mode fiber 1310 nm optical technologies have been employed for short-reach (xe2x80x9cSRxe2x80x9d) and intermediate-reach (xe2x80x9cIRxe2x80x9d) links using the abundance of unused dark fiber available in existing network infrastructures, such as may be found in MAN infrastructures. In this regard, 1310 nm-based optical solutions are denser and more power efficient than 1550 nm-based DWDM solutions. Furthermore, it is less expensive to utilize a separate fiber and 1310 nm optics for transmission of an additional signal in an environment where the separate fiber is already installed and available.
However, despite the implementation of 1310 nm-based optical technologies, service providers still face the problem of how to deploy more 1310 nm interconnects at is higher speed and lower cost per bit within the same or smaller physical space, and in a manner that takes advantage of reductions that have been achieved in integrated circuit scale. Smaller systems consume less floor space and power, enabling telecommunications companies to minimize lease expenses for equipment space. Shrinking system footprints also enable carriers to migrate to smaller facilities located nearer to users at the network edge. Optical connectors and associated optical modules have been developed in an attempt to respond to market needs. For example, 1310 nm fiber optic communication technology is now commonly implemented using small form factor (xe2x80x9cSFFxe2x80x9d) connectors, which support two optical fibers within a connector width of approximately 0.55 inches. However, even with use of SFF connector technology, port density improvements have not kept pace with corresponding improvements in scale that have been achieved in integrated circuit design.
Disclosed herein are systems and methods for optical communication that employ parallel fiber optic arrays to couple together two or more optical communication modules via physically distinct and signal-independent optical communication paths in which each signal-independent optical communication path is capable of transporting one or more signals that are separate and independent from other optical communications paths. The disclosed systems and methods may be advantageously implemented to provide a much denser and more power efficient optical interconnect solution for high speed/multi-port optical systems than is available using conventional technology and, in doing so, may be implemented to allow system providers to overcome existing barriers to improvements in density, power efficiency and cost effectiveness. The physically distinct and signal-independent optical communication paths provided by the disclosed systems and methods also make possible increased flexibility in system architecture.
In one disclosed embodiment, parallel fiber optic connectors may be employed in combination with fiber optic arrays to enable much higher port densities and greater power efficiency than is possible using existing SFF-based devices. For example, commercially available parallel fiber optic connectors commonly employed in single point-to-point parallel ribbon fiber applications (e.g., conventional MTP(trademark) connectors that support up to 12 single-mode fibers in a single ferrule and connector) may be employed to provide separate signal-independent communication paths having transmission characteristics that meet the much more demanding standards required for single fiber single point-to-single point applications, e.g., standards such as may be set by IEEE, ITU and ANSI standards bodies. Surprisingly, such single point-to-point connectors may be used in the disclosed systems and methods to provide multiple (e.g., non-single point-to-single point) communication paths that are physically distinct and signal-independent from each other while also being standards-compliant for each path. In one embodiment, such connectors may also be employed in a manner to support or enable up to four times the number of ports on a card edge as compared to an alternative design based on small form factor devices.
In another disclosed embodiment, parallel fiber optic connectors may be employed in combination with vertical-cavity surface-emitting lasers (xe2x80x9cVCSELsxe2x80x9d) to provide multiple signal-independent optical communication paths in a high density single mode configuration that offers smaller size and reduced power consumption at a lower cost than traditional SFF-based implementations. Using VCSELs enables multiple optical transmitters to be integrated into a single transmit module to which a parallel fiber optic connector, such as an MTP(trademark) connector, may be coupled to provide an independent optical transmitter for each fiber optic port of an MTP(trademark) connector array. In such an implementation, two or more 1310 nm-based transmit and receive array modules (e.g., based on 1310 nm VCSEL technology) may be coupled together, for example, using MTP(trademark) connectors in conjunction with industry standard single and/or duplex fiber connectors. When compared to conventional 1310 nm SFF-based transceivers, such an implementation may be used to realize system-level improvements such as increased system level densities, reduced power supplies, elimination of cooling fans, lower system costs, smaller system footprint for remote and/or space-restricted locations (e.g., remotely located pedestals, distribution cabinets in a multi-tenant unit or corporate campus, elevated installations on utility poles, etc.), increased battery back up time for remote systems, and/or greatly simplified fiber management.
Thus, the disclosed systems and methods may be advantageously used to enable many more signal-independent optical ports to be integrated into a single optical communication system than is possible with existing optical communication technologies such as conventional SFF-based technology. Furthermore, benefits of lower cost per port and lower cost per bit may be realized using the disclosed systems and methods because the cost of supporting functions including power supplies, fans, printed circuit boards, and chassis may be spread across a larger number of ports.
Another benefit that may be additionally or alternatively realized using the disclosed systems and methods is simplification of the management of fiber optic cables attached to a optical communication system that includes one or more optical communication modules. For example, in one embodiment the bulk, weight, cost, and complexity associated with fiber optic cabling may be greatly reduced by bundling multiple independent fibers into a single ribbon cable for coupling to an optical communication module. Individual fibers of a single ribbon cable may then be split apart or otherwise separated at a point removed from the optical communication system, e.g., split out at a patch panel with a simple fan out cable assembly for routing to different locations.
In one respect, disclosed is a fiber optic communication assembly, including: an optical communication module having a plurality of at least three fiber optic ports, the plurality of fiber optic ports being configured as an array, at least a first one of the plurality of fiber optic ports being signal-independent from at least a second one of the fiber optic ports; and a plurality of fiber optic conductors each having a first end and a second end providing an optical communication path therebetween, each of the plurality of fiber optic conductors being coupled at its first end to one of the plurality of fiber optic ports, the first ends of the plurality of fiber optic conductors being disposed in adjacent parallel relationship at the plurality of fiber optic ports. A first one of the fiber optic conductors of the fiber optic communication assembly may be coupled to the first one of the plurality of fiber optic ports to form a first signal-independent optical communication path, and a second one of the plurality of fiber optic conductors may be coupled to the second one of the plurality of fiber optic ports to form a second signal independent optical communication path. The second end of the first fiber optic conductor may be configured to be disposed in remote physical relationship to the second end of the second fiber optic conductor.
In another respect, disclosed herein is an optical communication system, including: a first optical communication module having a plurality of at least three fiber optic ports, the plurality of fiber optic ports being configured as an array, at least a first one of the plurality of fiber optic ports being signal-independent from at least a second one of the fiber optic ports; and a plurality of fiber optic conductors each having a first end and a second end providing an optical communication path therebetween, each of the plurality of fiber optic conductors being coupled at its first end to one of the plurality of fiber optic ports, the first ends of the plurality of fiber optic conductors being disposed in adjacent parallel relationship at the plurality of fiber optic ports. A first one of the fiber optic conductors of the optical communication system may be coupled to the first one of the plurality of fiber optic ports to form a first signal-independent optical communication path, and a second one of the plurality of fiber optic conductors may be coupled to the second one of the plurality of fiber optic ports to form a second signal independent optical communication path The second end of the first fiber optic conductor may be coupled to a first fiber optic port of a second communication module to form the first signal-independent optical communication path between the first communication module and the second communication module. The second end of the second fiber optic conductor may be coupled to a first fiber optic port of a third communication module to form the second signal-independent optical communication path between the first communication module and the third communication module.
In another respect, disclosed is a method of optical communication, including providing an optical communication module having a plurality of at least three fiber optic ports, the plurality of fiber optic ports being configured as an array and being coupled to plurality of fiber optic conductors each having a first end and a second end providing an optical communication path therebetween, each of the plurality of fiber optic conductors being coupled at its first end to one of the plurality of fiber optic ports, the first ends of the plurality of fiber optic conductors being disposed in adjacent parallel relationship at the plurality of fiber optic ports, a first one of the fiber optic conductors being coupled to a first one of the plurality of fiber optic ports to form a first optical communication path, and a second one of the plurality of fiber optic conductors being coupled to a second one of the plurality of fiber optic ports to form a second optical communication path, the second end of the first fiber optic conductor being disposed in remote physical relationship to the second end of the second fiber optic conductor. The method of this embodiment may also include transmitting or receiving a first optical signal at the first fiber optic port of the first optical communication module through the first optical conductor, the first optical signal being signal-independent from an optical signal transmitted or received at the second fiber optic port of the first optical communication module.
In another respect, disclosed herein is a fiber optic communication assembly, including: an optical communication module having a plurality of fiber optic ports, the plurality of fiber optic ports being configured as a single-wafer array, at least a first one of the plurality of fiber optic ports being signal-independent from at least a second one of the fiber optic ports; a plurality of fiber optic conductors each having a first end and a second end providing an optical communication path therebetween, each of the plurality of fiber optic conductors being coupled at its first end to one of the plurality of fiber optic ports, the first ends of the plurality of fiber optic conductors being disposed in adjacent parallel relationship at the plurality of fiber optic ports. A first one of the fiber optic conductors of the fiber optic communication assembly may be coupled to the first one of at the plurality of fiber optic ports to form a first signal-independent optical communication path, and a second one of the plurality of fiber optic conductors may be coupled to the second one of the plurality of fiber optic ports to form a second signal independent optical communication path. The first signal-independent optical communication path may be physically distinct from the second signal-independent optical communication path.